The Rod-Temperature Fire Detector reacts to absolute temperature as well as to temperature rise and thus combines the positive performance characteristics of conventional heat sensitive detectors and differential detectors.
The Rod-Temperature Fire Detector operates according to so-called principle of differential expansion principle. It consists of a preformed concave or convex contact system with low coefficients of expansion housed inside a feeler tube whose coefficients of expansion are high . The contact system is anchored to the fronted of the feeler tube.
When heated, then yields a different linear expansion, which leads to the clamping of the contact system, and thus depending on the type for closing or opening of the contacts. The response level (60°C/ 71°C / 88°C / 107°C / 135°C / 162°C) is preset by the factory.
The alarm is the earlier, the faster the temperature rise.
Through a balanced design, the system is tuned so that through immediate, harmless temperature effects (e.g. as warm air when opening an oven door) no alarm is triggered.